/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
 *
 * Project Info:  http://www.jfree.org/jfreechart/index.html
 *
 * This library is free software; you can redistribute it and/or modify it 
 * under the terms of the GNU Lesser General Public License as published by 
 * the Free Software Foundation; either version 2.1 of the License, or 
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but 
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
 * USA.  
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
 * in the United States and other countries.]
 *
 * ---------------------------
 * StackedXYAreaRenderer2.java
 * ---------------------------
 * (C) Copyright 2004, 2005, by Object Refinery Limited and Contributors.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited), based on 
 *                   the StackedXYAreaRenderer class by Richard Atkinson;
 * Contributor(s):   -;
 *
 * $Id: StackedXYAreaRenderer2.java,v 1.6.2.2 2005/10/25 20:56:21 mungady Exp $
 *
 * Changes:
 * --------
 * 30-Apr-2004 : Version 1 (DG);
 * 15-Jul-2004 : Switched getX() with getXValue() and getY() with 
 *               getYValue() (DG);
 * 10-Sep-2004 : Removed getRangeType() method (DG);
 * 06-Jan-2004 : Renamed getRangeExtent() --> findRangeBounds (DG);
 * 28-Mar-2005 : Use getXValue() and getYValue() from dataset (DG);
 * 03-Oct-2005 : Add entity generation to drawItem() method (DG);
 * 
 */

package org.jfree.chart.renderer.xy;

import java.awt.Graphics2D;
import java.awt.Paint;
import java.awt.Shape;
import java.awt.geom.GeneralPath;
import java.awt.geom.Rectangle2D;
import java.io.Serializable;

import org.jfree.chart.axis.ValueAxis;
import org.jfree.chart.entity.EntityCollection;
import org.jfree.chart.labels.XYToolTipGenerator;
import org.jfree.chart.plot.CrosshairState;
import org.jfree.chart.plot.PlotRenderingInfo;
import org.jfree.chart.plot.XYPlot;
import org.jfree.chart.urls.XYURLGenerator;
import org.jfree.data.Range;
import org.jfree.data.xy.TableXYDataset;
import org.jfree.data.xy.XYDataset;
import org.jfree.ui.RectangleEdge;
import org.jfree.util.PublicCloneable;

/**
 * A stacked area renderer for the {@link XYPlot} class.
 */
public class StackedXYAreaRenderer2 extends XYAreaRenderer2 
                                    implements Cloneable, 
                                               PublicCloneable,
                                               Serializable {

    /** For serialization. */
    private static final long serialVersionUID = 7752676509764539182L;
    
    /**
     * Creates a new renderer.
     */
    public StackedXYAreaRenderer2() {
        this(null, null);
    }

    /**
     * Constructs a new renderer.
     *
     * @param labelGenerator  the tool tip generator to use.  <code>null</code>
     *                        is none.
     * @param urlGenerator  the URL generator (<code>null</code> permitted).
     */
    public StackedXYAreaRenderer2(XYToolTipGenerator labelGenerator, 
                                  XYURLGenerator urlGenerator) {
        super(labelGenerator, urlGenerator);
    }

    /**
     * Returns the range of values the renderer requires to display all the 
     * items from the specified dataset.
     * 
     * @param dataset  the dataset (<code>null</code> permitted).
     * 
     * @return The range (or <code>null</code> if the dataset is 
     *         <code>null</code> or empty).
     */
    public Range findRangeBounds(XYDataset dataset) {
        double min = Double.POSITIVE_INFINITY;
        double max = Double.NEGATIVE_INFINITY;
        TableXYDataset d = (TableXYDataset) dataset;
        int itemCount = d.getItemCount();
        for (int i = 0; i < itemCount; i++) {
            double[] stackValues = getStackValues(
                (TableXYDataset) dataset, d.getSeriesCount(), i
            );
            min = Math.min(min, stackValues[0]);
            max = Math.max(max, stackValues[1]);
        }
        return new Range(min, max);
    }

    /**
     * Returns the number of passes required by the renderer.
     * 
     * @return 1.
     */
    public int getPassCount() {
        return 1;
    }

    /**
     * Draws the visual representation of a single data item.
     *
     * @param g2  the graphics device.
     * @param state  the renderer state.
     * @param dataArea  the area within which the data is being drawn.
     * @param info  collects information about the drawing.
     * @param plot  the plot (can be used to obtain standard color information 
     *              etc).
     * @param domainAxis  the domain axis.
     * @param rangeAxis  the range axis.
     * @param dataset  the dataset.
     * @param series  the series index (zero-based).
     * @param item  the item index (zero-based).
     * @param crosshairState  information about crosshairs on a plot.
     * @param pass  the pass index.
     */
    public void drawItem(Graphics2D g2,
                         XYItemRendererState state,
                         Rectangle2D dataArea,
                         PlotRenderingInfo info,
                         XYPlot plot,
                         ValueAxis domainAxis,
                         ValueAxis rangeAxis,
                         XYDataset dataset,
                         int series,
                         int item,
                         CrosshairState crosshairState,
                         int pass) {

        // setup for collecting optional entity info...
        Shape entityArea = null;
        EntityCollection entities = null;
        if (info != null) {
            entities = info.getOwner().getEntityCollection();
        }

        TableXYDataset tdataset = (TableXYDataset) dataset;
        
        // get the data point...
        double x1 = dataset.getXValue(series, item);
        double y1 = dataset.getYValue(series, item);
        if (Double.isNaN(y1)) {
            y1 = 0.0;
        }        
        double[] stack1 = getStackValues(tdataset, series, item);
        
        // get the previous point and the next point so we can calculate a 
        // "hot spot" for the area (used by the chart entity)...
        double x0 = dataset.getXValue(series, Math.max(item - 1, 0));
        double y0 = dataset.getYValue(series, Math.max(item - 1, 0));
        if (Double.isNaN(y0)) {
            y0 = 0.0;
        }
        double[] stack0 = getStackValues(
            tdataset, series, Math.max(item - 1, 0)
        );
        
        int itemCount = dataset.getItemCount(series);
        double x2 = dataset.getXValue(
            series, Math.min(item + 1, itemCount - 1)
        );
        double y2 = dataset.getYValue(
            series, Math.min(item + 1, itemCount - 1)
        );
        if (Double.isNaN(y2)) {
            y2 = 0.0;
        }
        double[] stack2 = getStackValues(
            tdataset, series, Math.min(item + 1, itemCount - 1)
        );

        double xleft = (x0 + x1) / 2.0;
        double xright = (x1 + x2) / 2.0;
        double[] stackLeft = averageStackValues(stack0, stack1);
        double[] stackRight = averageStackValues(stack1, stack2);
        double[] adjStackLeft = adjustedStackValues(stack0, stack1);
        double[] adjStackRight = adjustedStackValues(stack1, stack2);
        
        RectangleEdge edge0 = plot.getDomainAxisEdge();
        float transX1 = (float) domainAxis.valueToJava2D(x1, dataArea, edge0);
        float transXLeft 
            = (float) domainAxis.valueToJava2D(xleft, dataArea, edge0);
        float transXRight
            = (float) domainAxis.valueToJava2D(xright, dataArea, edge0);
        float transY1;
        
        RectangleEdge edge1 = plot.getRangeAxisEdge();
        
        GeneralPath left = new GeneralPath();
        GeneralPath right = new GeneralPath();
        if (y1 >= 0.0) {  // handle positive value
            transY1 = (float) rangeAxis.valueToJava2D(y1 + stack1[1], dataArea, 
                    edge1);
            float transStack1 = (float) rangeAxis.valueToJava2D(
                stack1[1], dataArea, edge1
            );
            float transStackLeft = (float) rangeAxis.valueToJava2D(
                adjStackLeft[1], dataArea, edge1
            );
            
            // LEFT POLYGON
            if (y0 >= 0.0) {
                double yleft = (y0 + y1) / 2.0 + stackLeft[1];
                float transYLeft 
                    = (float) rangeAxis.valueToJava2D(yleft, dataArea, edge1);
                left.moveTo(transX1, transY1);
                left.lineTo(transX1, transStack1);
                left.lineTo(transXLeft, transStackLeft);
                left.lineTo(transXLeft, transYLeft);
                left.closePath();
            }
            else {
                left.moveTo(transX1, transStack1);
                left.lineTo(transX1, transY1);
                left.lineTo(transXLeft, transStackLeft);
                left.closePath();
            }

            float transStackRight = (float) rangeAxis.valueToJava2D(
                adjStackRight[1], dataArea, edge1
            );
            // RIGHT POLYGON
            if (y2 >= 0.0) {
                double yright = (y1 + y2) / 2.0 + stackRight[1];
                float transYRight 
                    = (float) rangeAxis.valueToJava2D(yright, dataArea, edge1);
                right.moveTo(transX1, transStack1);
                right.lineTo(transX1, transY1);
                right.lineTo(transXRight, transYRight);
                right.lineTo(transXRight, transStackRight);
                right.closePath();
            }
            else {
                right.moveTo(transX1, transStack1);
                right.lineTo(transX1, transY1);
                right.lineTo(transXRight, transStackRight);
                right.closePath();
            }
        }
        else {  // handle negative value 
            transY1 = (float) rangeAxis.valueToJava2D(y1 + stack1[0], dataArea,
                    edge1);
            float transStack1 = (float) rangeAxis.valueToJava2D(
                stack1[0], dataArea, edge1
            );
            float transStackLeft = (float) rangeAxis.valueToJava2D(
                adjStackLeft[0], dataArea, edge1
            );

            // LEFT POLYGON
            if (y0 >= 0.0) {
                left.moveTo(transX1, transStack1);
                left.lineTo(transX1, transY1);
                left.lineTo(transXLeft, transStackLeft);
                left.clone();
            }
            else {
                double yleft = (y0 + y1) / 2.0 + stackLeft[0];
                float transYLeft = (float) rangeAxis.valueToJava2D(
                    yleft, dataArea, edge1
                );
                left.moveTo(transX1, transY1);
                left.lineTo(transX1, transStack1);
                left.lineTo(transXLeft, transStackLeft);
                left.lineTo(transXLeft, transYLeft);
                left.closePath();
            }
            float transStackRight = (float) rangeAxis.valueToJava2D(
                adjStackRight[0], dataArea, edge1
            );
            
            // RIGHT POLYGON
            if (y2 >= 0.0) {
                right.moveTo(transX1, transStack1);
                right.lineTo(transX1, transY1);
                right.lineTo(transXRight, transStackRight);
                right.closePath();
            }
            else {
                double yright = (y1 + y2) / 2.0 + stackRight[0];
                float transYRight = (float) rangeAxis.valueToJava2D(
                    yright, dataArea, edge1
                );
                right.moveTo(transX1, transStack1);
                right.lineTo(transX1, transY1);
                right.lineTo(transXRight, transYRight);
                right.lineTo(transXRight, transStackRight);
                right.closePath();
            }
        }

        //  Get series Paint and Stroke
        Paint itemPaint = getItemPaint(series, item);
        if (pass == 0) {
            g2.setPaint(itemPaint);
            g2.fill(left);
            g2.fill(right);
        } 
        
        // add an entity for the item...
        if (entities != null) {
            GeneralPath gp = new GeneralPath(left);
            gp.append(right, false);
            entityArea = gp;
            addEntity(entities, entityArea, dataset, series, item, 
                    transX1, transY1);
        }

    }

    /**
     * Calculates the stacked value of the all series up to, but not including 
     * <code>series</code> for the specified item. It returns 0.0 if 
     * <code>series</code> is the first series, i.e. 0.
     *
     * @param dataset  the dataset.
     * @param series  the series.
     * @param index  the index.
     *
     * @return The cumulative value for all series' values up to but excluding 
     *         <code>series</code> for <code>index</code>.
     */
    private double[] getStackValues(TableXYDataset dataset, 
                                    int series, int index) {
        double[] result = new double[2];
        for (int i = 0; i < series; i++) {
            double v = dataset.getYValue(i, index);
            if (!Double.isNaN(v)) {
                if (v >= 0.0) {
                    result[1] += v;   
                }
                else {
                    result[0] += v;   
                }
            }
        }
        return result;
    }
    
    /**
     * Returns a pair of "stack" values calculated from the two specified pairs.
     * 
     * @param stack1  the first stack pair.
     * @param stack2  the second stack pair.
     * 
     * @return A pair of average stack values.
     */
    private double[] averageStackValues(double[] stack1, double[] stack2) {
        double[] result = new double[2];
        result[0] = (stack1[0] + stack2[0]) / 2.0;
        result[1] = (stack1[1] + stack2[1]) / 2.0;
        return result;
    }

    /**
     * Returns a pair of "stack" values calculated from the two specified pairs.
     * 
     * @param stack1  the first stack pair.
     * @param stack2  the second stack pair.
     * 
     * @return A pair of average stack values.
     */
    private double[] adjustedStackValues(double[] stack1, double[] stack2) {
        double[] result = new double[2];
        if (stack1[0] == 0.0 || stack2[0] == 0.0) {
            result[0] = 0.0;   
        }
        else {
            result[0] = (stack1[0] + stack2[0]) / 2.0;
        }
        if (stack1[1] == 0.0 || stack2[1] == 0.0) {
            result[1] = 0.0;   
        }
        else {
            result[1] = (stack1[1] + stack2[1]) / 2.0;
        }
        return result;
    }

    /**
     * Returns a clone of the renderer.
     *
     * @return A clone.
     *
     * @throws CloneNotSupportedException  if the renderer cannot be cloned.
     */
    public Object clone() throws CloneNotSupportedException {
        return super.clone();
    }

}
